Circular polarisation in a sunspot

Swedish 1-m Solar Telescope/CRISP

Here we see how a sunspot and its surroundings look when using a special instrument that measures polarisation. Light is more polarised the more the waves that constitute it oscillate in the same way. Magnetic fields tend to generate polarised light and thus special images like these reveal beautiful hidden magnetic features in the atmosphere of the Sun. Such features have allowed us to understand the way magnetic fields and the bubbling from convection push each other, structuring sunspots, the largest features visible on the solar surface, often much larger than the Earth itself.

This observation was made with the CRISP instrument at the Swedish 1-m Solar Telescope in the Fe I 6301 and 6302 Å lines and corresponds to AR 11072.

Image credit: Vasco Henriques (ISP/Stockholm)

Publication: Vasco Henriques, PhD Thesis, ISP/Stockholm University